In certain cases, questions will arrive with untagged, such as via migration and no destination tag, or the only tag being removed. This leaves questions in the untagged state, which desires a fix. Often, these tags take while to remove due to the lack of attention to them. It would help to have them enter a separate review task so they can be quickly and easily tagged by human attention.
I would like to point out what I feel is an issue with the currently accepted answer (no offense intended, please see my quote only as an opinion).
Let me quote:
There are currently 167 untagged questions, well 164. The vast majority (all, bar maybe this one but I have no idea what's going on in it) are Off-Topic or Not Constructive.
This indeed indicates that about 150 questions are deletable/closeable. But also seems to forget the situation on other sites. If you go outside the main site, untagged questions are for the most migrated questions - for example on SharePoint overflow as now we have 39 untagged questions that no one retagged. I know, 39 is a small number, but consider that compared to stackoverflow all SharePoint overflow is made of small numbers. Problem is: those questions were migrated because on the migrated site they are reasonable and shouldn't be closed/deleted - the whole idea behind migration is to salvage a question that may otherwise die.
I personally see an incentive to retag untagged questions as useful. It doesn't need to be a whole new review task (for example I have the untagged task as a favorite, so a simple search is enough), but a badge could give people the needed incentive to perform some cleanup.
Somebody suggested that question cannot be migrated if no tag exist on the migration site, and thus cannot end up as untagged because of migration. I would disagree. Don't have the rep to check, but I assume that at last diamond-puyonbearded-unicorned-mega-admins can. This was migrated, and ended up untagged on SharePoint.
The original post had a SharePoint tag, that doesn't exist on the other side.
Is this really necessary when, in the past, there hasn't been a review system for these posts, and their count is only at 164?
I simply question whether it would be a rapidly growing list, like suggested edits. A few people could spend a day or two going through the tag page and doing this themselves, and even earn a badge for it.
I just don't see the significance of this if the list isn't growing quickly anyways, and migrations aren't happening all too often.
I think it would probably be better if all untagged questions were automatically closed and therefore appeared in the delete / re-open queues.
At least then there's no work needed to create a new queue and if most of them deserve deletion they're in the right place.
ObsessiveFOSS has suggested, in the comments, a single automatic close-vote rather than a blunderbuss full. This works slightly better as you then have to have a number of people decide to close in keeping with the community closing ethos. They then appear auto-magically in a review queue.